Two fighter jets operated by Islamic State militants were shot down by Syria's air force in the north of the country on Tuesday, Information Minister Omran Zoabi said in remarks published on Syria's state news agency SANA.

The report comes after a human rights group claimed last week that ISIS had stolen three warplanes, believed to be MiG-21 and MiG-23 jets, from Syrian army bases, according to Agence France-Presse. But the statements had not been independently verified.

Iraqi pilots, who had trained under former Iraqi President Saddam Hussein and have allegedly joined the terrorist organization, had been providing the jihadists with flying lessons at an air base in Aleppo province, the Britain-based Syrian Observatory for Human Rights said.

While two of the fighter jets had been destroyed, a third one remained at large as the Syrian air force conducted a search on Wednesday, Zoabi said.

"The terrorists were flying three old planes but our Syrian Arab Army aircraft immediately took off and destroyed two of them as they were landing in al-Jarrah military air base in Aleppo. The third plane was hidden" by the jihadists, Zoabi said. 

"It does not worry us and (the planes) cannot be used," he said, downplaying the threat from the third "unusable" plane. 

However, U.S. Central Command said that it was not aware of Islamic State flying jets in Syria, Reuters reported.

"We're not aware of ISIL conducting any flight operations in Syria or elsewhere," Patrick Ryder, a spokesman from Central Command, told the news agency.

Islamic State, which has seized swaths of land in Syria and Iraq, has been battling U.S.-led forces from multiple military bases for weeks by regularly using weaponry captured from the Syrian and Iraqi armies.

"We continue to keep a close eye on ISIL activity in Syria and Iraq and will continue to conduct strikes against their equipment, facilities, fighters and centers of gravity, whatever they may be," Ryder told Reuters.